Treatment of alkali soluble cellulose ethers



Patented Dec. 9, 1941 2,265,919 TREATMENT or ALKALI SOLUBLE CELLU- LOSEETHERS Leon Lilienield, Vienna, Austria; Antonie Lilienof said LeonLilienield, deceased, assignor to Lilienield Patents Inc., Boston,Mass., a corporation of Massachusetts No Drawing. Application August 17,1937, Serial No. 159,606. In Great'Britain September 2,

feld, administratrix 2 Claims.

.in water and processes for making same and processes for convertingthem into shaped structures are for the first time described in my U. S.Patents Nos. 1,722,927 and 1,722,928. a

Finally, hydroxy-paraflin-monocarboxylic acid derivatives of cellulosewhich are soluble in caustic alkali solutionbut which are insoluble oronly scarcely soluble in water and processes for making same andprocesses for converting them into shaped structures are for the firsttime described in my U. S. Patents Nos. 1,682,292, 1,682,293 andAlkali-solubility of cellulose ethers attended by insolubility in wateris in a functional relationship to' the number of hydroxyl hydrogenatoms of cellulose which are substituted by alcohol radicals. It may betaken as a general rule that, in most cases, alkali-soluble celluloseethers do not contain substantially more than one (and usually containless than one) alcohol radical introduced ether fashion per oneCsHioos-molecular unit of cellulose.

My research-work on alkali-soluble cellulose ethers, which by now hasextended over about 19 years, has shown that such alkali-solublecellulose ethers as .contain not more than one alcohol radicalintroduced ether fashion into the cellulose molecule per about 2, andpreierably not more than one introduced alcohol radical per about 4 to 5CeHmOs-molecular units of cellulose, are particularly valuable parentmaterials for the preparation of shaped structures.

But even such alkali-soluble cellulose ethers. as

contain not more than one introduced alcohol radical per about 8 to 10or 15, and. even about 16 to 30 and more CsHmOs-molecular units ofcellulose, have proved technically valuable.

The correctness of my theory illustrated above by figures, thatalkali-solubility in conjunction with prominent technical utility existsin cellulose ethers only when they contain less, preferf cellulose,follows i. a. from the fact that,.guided by the conception of theinterdependence between solubility in caustic alkali solution on the onehand and the ratio of introduced alcohol radicals on the other, sincethe beginning of my research-work on alkali-soluble cellulose ethers Ihave used proportions of etherifying agents which, from the outset,warrant such ratios of introduced alcohol radicals as come within thescope of the ratios set forth in the foregoing paragraph.

. In this respect and with regard to alkyl ethers of cellulose, I referby way of example to the Examples I, II and III of my U. S. Patent No.

1,589,606 of June 22, 1906, filed March 20, 1922 (convention date April2, 1921), in whose lower limit one mol. of ethyl chloride is used per3.18 C5H1oO5-molecular units of cellulose, or to the Example VII of samespecification, in whose lower limit one molecule of di-ethyl sulphate isused per 3.33 Cameos-molecular units of cellulose, further to theExamples I to III, V, VI and IX of my 7 U. S. Patent No. 1,683,831 ofSept. 11, 1928, iiled June 16, 1923 (convention date: July 13, 1922) inwhich one mol. of ethyl chloride is used per 1.316 or 2.632 or 3.95 or1.6 respectively CsH1oO5-mO- lecular units of cellulose, further to theExamples 1 to 19 of my U. S. application Ser. No. 521,023 of March 7,1931 (convention date: March 15 1930, corresponding to British PatentNo. 357,167) and to the Examples I and II of my U. S. application Ser.No. 521,017 of same date, correspondcohol radical per oneceHioos-molecular unit of ing to British Patent No. 357,527, and to theExamples 1 to 6 and 10 to 12 of my U. S. application Ser. No.- 521,022of March 7, 1931 (convention date: March 14, 1930), corresponding toBritish BatentNo. 374,964 in which one mol. of (ii-methyl sulphate ordi-ethyl sulphate is used per 1.28 or 1.57 or 2.56 or 3.15 or 4.75 or5.16 or 7.7 or 9.51 or 15.5 C6H1n05-molecular units of cellulose andfinally to my U; S. application Ser. No. 71,254 of March 27, 1936(convention date: March 29, 1935) corresponding to British Patent No.459,122 in which proportions of ethylating agents smaller than one mol.of ethylating agent per 4 CsH1o05- molecular units of cellulose areused.

With regard to alkali-soluble hydroxy-alkyl ethers of cellulose, I referby way of example to the Examples 1 and 6 of my U. S. Patent No.1,722,927 of July 30, 1929, filed March 17, 1925 (convention date: April4, 1924), in which one mol. of alpha-mono-chlorohydrin is used per 2.5CsHmOs-molecular 'units of cellulose or'to the Example 5 of samespecification in whose lower limit one mol. of ethylene chlorohyclrin isused per 1.64 CeI-ImOs-molecularunits of cellulose or to the Examples 1to 3 and 17 to 19 of my U. S. Patent No. 1,858,097 of May 10, 1932,flied March 13, 1930 (convention date: March 16, 1929), in which onemol. of alpha-mono-chlorohydrin is used per 2.26 to 6.82CeI-ImOs-molecular units of cellulose and to the Examples 4 or 5 or 9 or11 of same specification in which one mol. of ethylene chlorohydrin isused per 1.65 or per 2.48 or per 4.96 Cameos-molecular units ofcellulose and finally to my U. S. application Ser. No. 71,255 of March2'7, 1936' (convention date: March 29, 1935) in which proportions ofhydroxy-alkylating agents smaller than one mol. of hydroxy-alkylatingagent per 9 Cameos-molecular units of cellulose are used.

Finally, with regard to hydroxy acid'ethers of cellulose, I refer by wayof example to the Exassume unit of cellulose contain less than oneetherwise introduced alcohol radical per one CeHroOsmolecular unit ofcellulose. In this respect attention is called for instance to the upperlimit of Example III of my U. S. Patent No. 1,589,606 in which one mol.of ethyl chloride is used per 0.88 CeHioOs-molecular units of celluloseand which example, nevertheless, produces an alkaliamples 1 to 3 of myU. S. Patent No. 1,682,292 of Aug. 28, 1928, filed July 23, 1924(convention date: April 4, 1924) in which one mol. of mono-chloroaceticacid is used per 1.14 or 5.5 or 5.39 respectively Cal-ImOs-molecularunits of cellulose.

Since, in the etherifying operation, not the whole amount of theetherifying agent is used up for the substitution of hydroxyl hydrogenatoms of the cellulose molecule, the number of the alcohol radicalswhich are contained in the cellulose ethers produced according to theaforementioned U. S. Patent No. 1,589,606 which theoretically,

should contain one ethyl group per 3.18 CeHioO5- molecular units ofcellulose, are found by analysis to contain one ethyl group per about11.1 (Example I) or 9.6 (Example II) or 8.54 (Example IIICameos-molecular units of cellulose) and that the products of theExamples 1 to 19 ofmy U. S. application Ser. No. 521,023, instead 'ofthe theoretical ratios set forth above, in analytical reality containone methyl group per 5.35 (instead of 1.28) or per 5.6 (instead of 2.56)or per 6.5 (instead of 5.16) or per 12.7 (instead of 7 .7)celimOs-molecular units of cellulose, and one ethyl group per 5.73(instead of 3.15) or per 3.54 (instead of 1.57) CaHmOs-molecular unitsof cellulose. I

By the foregoing statements-I do not mean to say that alkali-solublecellulose ethers cannot be produced by means of proportions ofetherifying agents equalling or exceeding one mol. of etherifying. agentper one CaHmOs-molecular unit of cellulose. For. when in the reactingmass the proportion of caustic alkali to cellulose and/or to water iskept' withinappropriate limits,

and when the time and temperature of the reaction are suitablychosen,jalkali-soluble cellulose ethers are obtained even when one ormore mol. of the etherlfying agent are used per one CnHroOs-molecularunit of cellulose. According to my present knowledge, as far as they areinsoluble in water and convertible into shaped structures or otheruseful articles possessing valuable properties, particularly a perfectlysatisfactory tensile strength in the dry and especially in the wet stateand a satisfactory extensibility. also such alkali-soluble celluloseethers as are prepared by means of proportions of etherifying agents notsmaller than, or exceeding. one mol. of etherifying agent per oneCerium-molecular soluble, water-insoluble, ethyl cellulose containingone ethyl group per 5.8 CaHmos-molecular units of cellulose, or toExample IA of my U. S. application Ser. No. 71,260 in which one mol. of

ethyl chlorideis used per 0.395 (lower limit) or per 0.197 (upper limit)Cameos-molecular units of cellulose and which example produces at or orC. alkali-soluble ethyl celluloses containing one ethyl group'per 9.8 to6.2 (lower limit) or per 7.7 to 4.99 (upper limit) CsHmOsmolecular unitsof cellulose. But even the alkalisoluble, water-insoluble ethylcelluloses of Ex- U. S. application Ser. No. 521,017 in which 3.05

ly mol. of di-ethyl sulphate are used per one CcHmOs-molecular unit ofcellulose and which per 3.37,. (Example VI) or per 10.57 and, when thetime of the reaction is 72 hours, per 3.9 (Example VII) CsHmOs-molecularunits of cellulose. ri'urther call attention to Examples 7 and 8 of myU. S. application Ser. No. 521,022 in which one mol. of di-methylsulphate is used per 0.77 (Example '7) or per 0.51 (Example 8 C6Hl005-molecular units of cellulose), whilst the alkalisoluble, water-insolublemethyl celluloses result ing from these examples contain one methylgroup per 3.28 (Example 7) or per 2.96 (Example 8) ,CsHioOs-molecularunits of cellulose, or to Example 9 of same specification in which onemol. of (ii-ethyl sulphate is used per 0.869 CeHmQs-molecular units ofcellulose and which nevertheless results in an alkali-soluble,waterinsoluble ethyl cellulose that contains one ethyl .agent per oneCaHmOs-molecular unit of cellulose, most of the alkali-soluble,water-insoluble cellulose ethers of the aforementioned types which areconvertible into shaped structures (such as artificial threads or filmor dressings of fabrics etc.) having perfectly satisfactory dynamometricproperties, are insoluble or practically insoluble or only incompletelyor partially soluble in caustic alkali solution at room temperature.

For example: Among those cellulose ethers which are incompletely orpartially soluble in caustic alkali solution, the proportion of the partwhich is soluble. in caustic alkali solution at room temperature to thepart which is insoluble in caustic alkali solution at room temperaturevaries in my aforementioned processes within very wide limits, forinstance between 40 to 90 per cent. of the soluble -to 60 to per cent.of the insoluble part (see for example the relative examples of my U. S.Patents Nos. 1,683,682 and 1,683,831) and in many instances even between10 to per cent. of the soluble to 90 to 80 per cent. of the insolublepart.

Consequently, since the separation of the cellulose ethers of theaforementioned types into their constituents which are soluble incaustic alkali solution at room temperature and into their constituentswhich are insoluble in caustic alkali solution at room temperaturecomplicates the process and, in most cases, entails a substantial lossof substance, soon after having @synthesized the first alkali-solublecellulose ethers, I had to look for a way towards bringing into solutionin caustic alkali solution the whole substance of the cellulose ethershaving the composition set forth in'the fourth, fifth and sixthparagraphs of this description. The outcome of my endeavours in thisdirection was the process laid down in my British Patent No. 212,864 ofMarch 15, 1923, which resides in my discovery that it is possible to'make the whole substance of the cellulose ethers of theaforementionedtypes soluble in caustic alkali solution at roomtemperature by contacting them with caustic alkali solution and coolingthe thus obtained suspensions or incomplete solutions toof theaforementioned types is due to thelr viscosity and to their physicalcharacter. These properties of the solutions have anunfavourableinfiuence not only on the filtering capacity, but, what ismore important, on the smoothness of the working up of the solutionsinto shaped structures, such as artificial threads or film or the like.For, it is not a rare occurrence that, owing to their slimy condition,the solu-' ble, water-insoluble cellulose ethers are exposed atemperature between plus 5 C. and minus (See additional cost whichweighs down the economy of the utilisation for practical purposes of thecellulose ethers of the aforementioned types; all

the more so, since most of these ethers can be made soluble orcompletely soluble in caustic alkali solution at room temperature onlyby cool-- ing their suspensions or incomplete solutions in causticalkali solution until freezing occurs. The temperatures meeting thisrequirement being very low (in general not higher than minus 10 C.) theadditional cost caused by the freezing operation is considerable;

In addition, (unless, owing to an unduly prolonged maturing of thealkali-cellulose and/or owing to the maturing of the alkali cellulosehaving been conducted at a temperature substantially exceeding roomtemperature, for example at or C. or higher, the cellulose component ofthe cellulose ethers of the aforementioned types is deeply degraded andtherefore the cellulose ethers or the shaped structures producedtherefrom little resistant to water) in many cases the filteringcapacity of the cellulose ether solutions is rather poor; so much so,that very frequently filtration through cotton wool is only possiblewith the aid of a pressure of 6 to 10 atmospheres or even more, andthat, notwithstanding,- the filtration proceeds very slowly and alsothis only, when the cotton wool is changed from time .to time.

It is highly probable'that the poor filtering capacity of the solutionsof the cellulose ethers to a temperature exceeding 40 C., or exceedingC. and preferably not lower than C.

Specifically the present invention is based on the conception (1) That,when cellulose ethers, which are insoluble or only incompletely orpartially soluble in caustic alkali solution at room temperature or atany'temperature between room temperature and the temperature at whichtheir suspensions or incomplete solutions in caustic alkali solutionfreeze or form crystals and which can be made soluble or completelysoluble in caustic alkali solution at room temperature and/or at atemperature between roomtemperae ture and the temperature at which theirsuspensions or incomplete solutions in caustic alkali solution freeze orform crystals by cooling their suspensions or incomplete solutions untilthey freeze or form crystals, are exposed to a temperature exceeding 400., or exceeding 80 C. andpreferably not lower than 100 C., celluloseethers are obtained which are soluble in caustic alkali solution at atemperature above the temperature at which their suspensions orincomplete solutions in caustic. alkali solution freeze or formcrystals,

perature, but which are soluble therein at a temperature between roomtemperature and the temperature at which their suspensions 'orincomplete solutions freeze or form crystals, are exposed toatemperature exceeding 40 C., or exceeding 80 'C. and preferably notlower than 100 C.,- cellulose ethers are obtained which are soluble incaustic alkali solution at a temperature which is higher than thetemperature at which the parent cellulose ethers are .soluble therein, r

(3) That, when (a) cellulose ethers, which are insoluble or onlyincompletely or partially soluble in caustic alkali solution at roomtemperature or at any temperature between room temperature and thetemperature at which their suspensions or incomplete solutions incaustic alkali solution freeze or form crystalsand which can be madesoluble or completely soluble in caustic alkali solution at roomtemperature or at a temperature between room temperature and thetemperature at which their suspensions or incomplet solutions in causticalkali solution freeze or form crystals by cooling their suspensions orincomplete solutions until they freeze or form crystals, or

(b) Cellulose ethers which are insoluble in caustic alkali solution atroom temperature, but

the parent cellulose ethers, and

(4) That, when cellulose ethers, which are insoluble or onlyincompleteLv or partially soluble in caustic alkali solution at room.temperature or at any temperature between room temperature and thetemperature at which their suspensions or incomplete solutions incaustic alkali solution freeze or form crystals and which can be madesoluble or completely soluble in caustic alkali solution at roomtemperature or at a temperature between room temperature and thetemperature at which suspensions or incomplete solutions in causticalkali solution freeze or form crystals by cooling their suspensions orincomplete solutions until they freeze or form crystals, are exposed toa temperature exceeding 40' C. or exceeding 80 C. and preferablynotlower than 100 0., without becoming soluble in caustic alkalisolution at a temperature above the temperature at which theirsuspensions or incomplete solutions in caustic alkali solutionfreeze orform crystals, cellulose ethers are ob-.. tained the solutions of whichhave a better filtering capacity and/or a lower viscosity and/or abetter spinnability than the parent cellulose ethers.

In other words:

The present process is based upon the specific inventive principle (1)That, when such alkali-soluble cellulose ethers as are insoluble or onlyincompletely or partially soluble in caustic alkali solution at roomtemperature or at any temperature between room temperature and thetemperature at which their suspensions or incomplete solutions incaustic alkali solutiom; freeze or form crystals and which can bemade'soluble or completely soluble in caustic alkali solution at roomtemperature or at a temperaturebetween room temperature and thetemperature at-which their suspensions or incomplete solutions incaustic alkali solution freeze or form crystals by cooling theirsuspensions or incomplete solutions until they freeze or form crystals,for example cellulose ethers containing not'more than one alcoholradical introduced ether fashion into the cellulose molecule per about2, preferably per about 5 and even per to or 16 to 30 CsHmOs-molecularunits of cellulose, are exposed to a temperature exceeding 40 C., orexceeding kali. and

(2) That, when such cellulose ethers, for example cellulose etherscontaining not more than one alcohol radical introduced ether fashioninto the cellulose molecule per about 2, preferably per about 5 and evenper 10 to 15 or 16 to 30 00111005- molecular units of cellulose, as aresoluble in caustic alkali solution at room temperature-or at atemperature between-room temperature and the freezing temperature oftheir suspensions or incomplete solutions in caustic alkali solution oras can only be made soluble in caustic alkali solution at roomtemperature or at a temperature between room temperature and thefreezing temperature by' refrigerating their suspensions or incompletesolutions in caustic alkali solution, are exposed to a temperatureexceeding 40 C., or exceeding 80 C. and preferably not lower than 100C., in some cases cellulose ethers are obtained which, although havingthe same solubility relationships as the parent cellulose ethers,display superior properties in other respects, particularly a superiorfiltering and/or a superior spinning capacity.

The present invention is further based on the observation that in manycases the improved solubility and/or filterability and/or spinnabilityof the cellulose ethers prepared according to the present invention maybe further ameliorated by after-treating them with one or moresubstances having acid reaction, such as dilute acids, or solutions ofacid salts at a temperature not substantially exceeding roomtemperature.

'Considerlng our knowledge regarding the effect of acid substances oncellulose derivatives, it is rather surprising that, in some cases, thedynamometric properties, particularly the wet tenacity and extensibilityof shaped structures made from such products of the invention as areafter-treated with a medium containing an acid or acid salt are betterthan the dynamometric properties of shaped structures produced fromproducts of the invention prepared in the same manner but notafter-treated with .an acid medium. v

The technical advances marked by, and thus the objects of, the presentinvention ms I. Improving the solubility and moving up the temperaturerequisite for the dissolution in caustic alkali solution of numerousalkali-soluble cellulose-ethers which are or can bedissolved onLv attemperatures below room temperature. In many cases, in which freezingand thawing is indispensable or at least helpful, this effect of theinvention allows of dispensing with thefreezing and liquefylng step inthe dissolving operation.

This important improvement can be realized also with such alkali-solublecellulose ethers as are prepared by means of highly reduced quantitiesof etherifying agents, for example by means of proportions ofetherifying agents which are not larger and preferably which. are evensmaller than one mol. of etherifylng agent per 4 to Comma-molecularunits of cellulose. 1

II. Amelioration of the filterability and spin-' nability of technicallysuitable alkali-soluble cellulose ethers, such cellulose ethers includedas (owing to their nature and/or to the fact that,

on being applied to them, the present process has not been driven farenough), on being treated according to the present process, are notimproved as set out above under 1 and/or such cellulose ethers includedas are soluble in caustic alkali solution at room temperature.

Other objects of the invention will become-apparent from the followingdescription.

ecution of the process, 1. e. to the particulars given therein as to thetypes of the alkali-soluble cellulose ethers (i. e. as to the nature ofthe alcohol radicalor radicals etherwise introduced into the cellulosemolecule and as to the representatives set forth by way of examples forthe various types of cellulose ethers and as to the processes or methodsfor the production of the cellulose ethers), as to the temperature ortemperatures and duration of the treatment of the cellulose ethersaccording to the present inven- I tion, as to the condition of thecellulose ethers during their exposure to heataccording to the presentprocess, as to details of the treatment according to the presentprocess, as to the substances which optionally may be added to thecellulose ethers before or during the treatment according to the presentprocess, as to the processes or methods and temperatures of thepreparation of the cellulose ether solutions, as to the quantitativecomposition of the cellulose ether solutions, as to the substances whichoptionally may be added-to the cellulose ether solutions, as to themethods of working up the cellulose ether solutions into shapedstructures or other useful articles, as to the methods of converting thecellulose ethers prepared according to the present invention into theirderivatives, such as xanthates, as to the methods for working up thecellulose ether xanthates made according-to the present invention into,shaped structures, as

to theafter-treatment oi the shaped structures vention in practicecomprises exposing one or more cellulose ethers of the aforementionedtypes to a temperature or temperatures exceeding C. or exceeding 80 C.and preferably not lower than 100 C. According to the present state ofmy knowledge, it seems that the bestresults are obtained at atemperature or temperatures lying between 100 and 160 C. But, when theduration of the heating operation is to be very short, for example 1hour or 30 minutes or 5 to 15 minutes, also higher temperatures, e. g.temperatures up to 200 to 250 C. may be used.

The cellulose ethers may be treated according to the present process inthe dry or air-dry or moist or wet condition. According to my presentknowledge, 1. e. to the experience gathered hitherto, it seems .that thebest results are obtained when the cellulose ethers of theaforementioned types are treated according to the present process in thedry or air-dry state.

The exposure of the cellulose ethers to heat according to the presentprocess may take place in the presence of air or of another gas (such ashydrogen or nitrogen or carbon dioxide) at atmospheric or at anincreased pressure or at a reduced pressure (i. e. in a more or lesscomplete 'vacuum) and may be effected in open vessels orin closedvessels, such as autoclaves, and may be conducted in perfect rest orwith continuous or intermittent stirring, kneading or otherwiseagitating, ,fo'l' example by allowing the vessel in which the heatingtakes place to rotate.

To accelerate and/or intensify the action of the heat on the celluloseether under treatment,

one or more catalyzers may be added to the cellulose ether, for examplea thorium salt or a cerium salt or a small quantity of an alcohol,suchas ethanol or methanol or glycol, or oi an inorganic or organic nitrogenbase,-for example ammonia or an alkyl amine, for example dimethyl amineor an aromatic base, for instance di-m'ethyl aniline or any othersuitable catalyzer.

The duration of the heating may be varied within wide limits and dependspartly on the nature and properties, particularly solubility andviscosity of thecellulose ether under treatment and partly on thedesired degree of the change in solubility and/or viscosity of thecellulose ether treated on the one hand, and on the temperature at whichthe heating operation is conducted on the other. The experience gatheredhitherto seems to indicate that the duration of the heating is ininverse proportion to the temperature. To give an example: Whereas aheating oi 2 to 3 hours at to C. suiiices to make certain hydroxy-ethylcelluloses which are soluble in caustic alkali solution only at lowtemperatures for example at 0 to minus 4 C., soluble in caustic alkalisolution at room temperature, a heating of at least 12 hours isnecessary to obtai the same result at 50 to 60 C.

The products of the invention may be worked up into shaped structures orother useful articles either without being subjected to anyaftertreatment or, if .desired, after having been washed or washed andthereafter dried.

As stated above, inmany cases, the products of the invention are furtherimproved by an after-treatment with a medium containing an acid or anacid salt. For this purpose an inorganic or organic acid may be used,for example hydrochloric acid or sulphuric acid of 0.2 to 10 per cent.strength or the like. Since, when applied at a temperature substantiallyexceeding room temperature, even very dilute acids, particularly mineralacids, exert a hydrolyzing action on the cellulose molecule contained inthe alkali-soluble cellulose ethers and, thus, greatly impair and inmany cases destroy their filmand thread forming properties and,accordingly, their suitability for the production of film, threads orthe like, not to damage the products of the present invention, thetreatment with acids and even with very dilute acids, particularlymineral acids, must be conducted at room temperature or at a temperaturebelow room temperature, at any rate at a temperature not substantiallyexceeding room temperature.

Good results are obtained, for instance, when the products of theinvention are treated with hydrochloric or sulphuric acid of 0.5 to 3per cent. strength at room temperature for, say, 2 to 12 hours.

It is to be understood that in the present invention alkali-solublecellulose ethers. may be used as parent materials which are madeby anyprocess or method whatever, for instance according to any one of theprocesses and/or methods described in my U. S. Patents Nos. 1,589,606,1,683,831, 1,683,682, 1,722,927, 1,682,292, and 1,682,294 or accordingto any one of the processes oi methods described in my U. S.applications Ser. Nos. 521,022, 521,026, 71,250, 71,251, 71,252, 71,253,71,254, 71,255, 71,260, 71,261, 71,262 and 91,790 or according to anyother process or ample at-a temperature between room temperature and C.or lower or such cellulose ethers A as are insoluble or incompletelysoluble in caustic alkali solution at room temperature, but as can bemade soluble or completely soluble therein at room temperature bycooling their suspen-' sions or incomplete solutions in caustic alkalisolution to a temperature between room temperature and 0 C. or to 0 C.or to a temperature below 0 C., for example to minus C. or to minus C.or lower and then allowing the temperature to rise to 0 C. or above 00., for example to room temperature, or such cellulose ethers as areinsoluble or incompletely soluble in caustic alkali solution at roomtemperature or at a temperature between room temperature and 0 C. oreven at 0 C., but as can be made partially or completely soluble thereinat room temperature and/or at a temperature between room temperature and0 C. or at 0 C. by cooling their suspensions or incomplete solutions toa temperature below 0' 0., for example to minus 5 C. or to minus 10 C.or lower and then allowing the tem-' perature to rise to 0 C. or above 0C. for example to room temperature.

In other words: In the present invention not only such alkali-solublecellulose ethers as can be prepared by the processes and methodsdescribed in the specifications set forth in the foregoing paragraph,but also such alkali-soluble cellulose ethers may be used as parentmaterials as can be prepared by any other process or method suitable forthe preparation of cellulose,

ethers which are at least partially soluble in caustic alkali solutionor can be made soluble thereinby application of low temperatures, forexample by the process described in my British Patent No. 212,864.

It is further to be understood that in the present invention eithersimple or mixed alkali-soluble cellulose ethers can be employed. Asmixed ethers the following may be named by way of example: i

Cellulose ethers containing in their molecule two different alkylgroups, cellulose ethers containing in their molecule two diiferenthydroxyalkyl groups, cellulose ethers containing in their molecule analkyl group and a hydroxy-alkyl group, cellulose ethers containing intheir molecule two different hydroxy-acid residues, cellulose etherscontaining in their molecule an alkyl group and a hydroxy-acid residue,cellulose ethers containing in their molecule a hydroxy-alkyl group anda hydroxy-carboxylic acid residue and so on.

These mixed ethers can be-obtained, for example, by treating alkalicellulose simultaneouslyor in either order with two different alkylatingagents, or with an alkylating agent and a hydroxy-alkylating agent, orwith two different hydroxy-alkylating agents, or with two diiferenthalogen fatty acids, or with an alkylating agent and a halogen fattyacid, or with a hydroxyalkylating agent and a halogen fatty acid, etc.,etc. In case of simultaneous treatment, the two different reagents maybe added to the alkali w a coagulating agent, for example one of theooagulating baths known in the art of making shaped structures fromalkali-soluble cellulose derivatives, alkali-soluble cellulose ethersin-,- cluded.

The cellulose ethers prepared according to the present invention may beworked up into shaped structures also in such a manner that their shapedsolutions are contacted with an agent or agents which has or have acoagulating effect on the shaped solution and a plasticizing effect onthe freshly coagulated material. As agents which exert a coagulating andplasticizing action, baths containing at least 25 per cent. of sulphuricacid monohydrate (for example 25 to about '70 per cent. of sulphuricacid monohydrate), or such a proportion of another strong mineral acidas will produce an effect in the manufacture of shaped structuressimilar to that given by sulphuric acid containing at least 25 per centof sulphuric acid, have proved suitable. The coagulating andplasticizing of the solution may also occur in two steps by acting uponthe shaped solution first with one or more agents which have acoagulating but no or only little plasticizing effect on the shapedsolution and then with one or more agents (for example strong mineralacids, particularly strong sulphuric acid) which have a plasticizingeifect on the freshly coagulated material.

'As far as supportless shaped structures, such as artificial threads,artificial hair, artificial straw, film bands, strips or the like areconcerned,

the shaping and coagulating may be effected by extruding the celluloseethersolution through suitably formed openings into a coagulating bath.Supportless shaped structures, such as film or strips or the like may bealso produced according to the invention by spreading the celluloseether solution on a smooth surface which is buing with the celluloseether solution a rigid or pliable support and, with or withoutintermediate drying, treating the material with a coagulating bath, byeither introducing'the material into the coagulating bath or by sprayingthe coagulating bath on the material or conducting cellulose together,for example mixed, or one the material through a mist of the coagulatingIt must be pointed out expressly that the working up of the celluloseethers prepared according to the present invention into shapedstructures may also be effected according to the processv described inmy U. 8. application Ser. No. 79,199, i. e. by coagulating a shapedsolution containing at least one cellulose derivative produced accordingto the present invention by a medium containing at least one alkalicarbonate or according to the process described in my U. S. applicationSer. No. 63,280, namely by introducing the shaped solution into water.

Any suitable softening agents, such as glycerine or a glycol or a sugar,such as glucose or asoap lose ethers prepared according to the presentinvention are xanthated, for example according to the processesdescribed in my U. S. Patents Nos. 2,021,861, 1,858,097 or 1,910,440 orin my U. S application Ser. No. 521,023.

The xanthates of the cellulose ethers prepared according to the presentinvention can be produced by acting on the cellulose ethers with carbonbisulphide in presence of alkali. The carbon bisulphide may be caused toact either upon the cellulose ethersin the solid form in presence ofcaustic alkali solution, for example upon a moist alkali compound of acellulose ether or upon a mixture of a cellulose ether with causticalkali solution or upon a suspension of a cellulose ether in causticalkali solution or upon a solution of a cellulose ether in causticalkali solution.

The methods of producing -xanthates of cellulose derivatives and theworking up of such xanthates into shaped structures are in the fouraforesaid specifications as well as in my U. S.

applications Ser. Nos. 71,250, 71,251, 11,252,

forth. It is to be understood that the'invention is not limited to theseexamples, to the precise proportions of ingredients, the times andtemperatures and sequence of steps set forth; the parts are by weight:

Example I A. 1000 parts of air-dry wood pulp of a quality and viscositycustomary in the viscose art or cotton linters of similar quality aresteepedin 10,000

to 20,000 parts of caustic soda solution of 18 per 7 cent. strength at10 C. and the mixture allowed to stand at 10 C. for l to 24 hours. Theresulting mass is then pressed at 10 C. to 3000 to 3500 parts andcomminuted at 10 C. for l to 3 hours in a Werner-Pfieiderer shredder oranother suitable comminuting machine or in a Werner- Pileidererxanthating machine whose blades may be dentated, whereafter the shreddedalkali cellulose is allowed to mature for '72 hours at 10 C. Thereupon200 parts of ethylene chlorohydrin or 110 parts of ethylene oxide areadded in one or several portions and the reaction mass is shredded forabout 3 hours at 10 C.

Thereafter the crude reaction mass as such or after having beenneutralised or acidified is washed with water and then pressed and driedat 100 C. for about 12 to 20 hours. Thereupon,

optionally after having been comminuted or and 71,264 described andillustrated by examples in so exhaustive a manner that, instead ofrepeating the said working formulae, I may safely limit myself toreferring to the respective parts of the said specifications which willserve as useful descriptions of, and examples for, the conversion intotheir xanthates of the alkali-soluble cellulose ethers preparedaccording to the present invention and the working up of the thusobtained xanthates into shaped structures.

, It must be pointed out expressly that the working up of the xanthatesof the cellulose ethers prepared according to the present invention intoshaped structures or other useful articles may also be effectedaccording to the processes described in my U. S. application Ser. No.90,819

or Ser. No. 90,820.

Any suitable softening agents, such as glycerine or a glycol or a sugar,such as glucose or a soap or Turkey-red oil, or a dry ng or non-dryingoil, or a. halogen derivative of a dior polyvalent alcohol, particularlya halohydrin, such as a dichlorohydrin' or a monochlorohydrin orethylene chlorohydrin may be added to the solutions of the xanthates ofthe cellulose derivatives produced according to the present invention.

With regard to the carryingout of the present invention in practice, itis impossible to indicate every condition for success in everyparticular case and it is to be understood that preliminary experimentscannot be avoided to find what are,

the conditions necessary for success when using a particular kind ofcellulose, a particular cellulose ether, a particular temperature and/orduration of the heating operation and/or a particular method of souring.

In order to explain the nature of the present invention, the followingspecific examples are set ground, the dried hydroxy-ethyl cellulose isplaced in a closed vessel and, optionally with stirring or kneading orotherwise agitating (for example in an autoclave which may be providedwith a stirring device orwhich may be a rotating autoclave or in akneading machine provided with a well fitting lid), heated to about 100C.

and kept at this temperature for 12 to 24 hours.

Whilst a slowly filterable solution in caustic soda solution of, say, 8to 9 per cent. strength of the parent hydroxy-ethyl cellulose can beobtained only by cooling its suspension or incomplete solution incaustic soda solution to minus 5 C. or preferably to minus 10 C. andallowing the temperature to rise to room temperature, the product ofthis example readily dissolves in caustic soda solution of 8 to 9 percent. strength at about 0 C., the thus obtained solution remainingperfectly liquid atroom temperature also.

In addition, whereas the viscosity of a solution containing 7 per cent.of the parent hydroxyethyl cellulose and 9 per cent. of NaOH is 25 to 28as compared with glycerine of 1.26 specific gravity, and whereas thissolution filters only at a pressure of about 10 atmospheres and alsothis very slowly (the cotton used for filtration must be changed 20 to30 times) the viscosity of a solution containing '7 per cent. of theproduct of this example and 9 per cent. of NaOH is about 8 to 9 ascompared with giy'cerine of 1.26 specific gravity and the solutionfilters verywell at a pressure of about 4 to 2 atmospheres and withoutany changes or with only a few changes of the cotton. From the solutionof the heat treated product of this example it is possible to obtainfilms which have a dry tenacity of 13000 grammes (13 kilogrammes) persquare millimetre, a wet tenacity of 3000 grammes (3 kilogrammes), persquare millimetre, a dry extensibility of 24 per cent. and a wetextensibility of to per cent.

B. The process is conducted as in A, but with r the variation that,before being dried, the parent I hydroxy-ethyl cellulose is, by treatingit once or several times with alcohol of 96 to 100 per cent. strength,partly or. wholly dehydrated and, optionally thereafter exhausted withether.

C. The process is conducted as in A or B, but withthe exception that theheating operation takes place in absence of air or in presence of apress or in a centrifuge and washed with water until free from acid. Thewashed product is then pressed and, after the water content of thepressed product has been determined, dissolved by mixing it at C. or atC. or at 15 C. with so much caustic soda solution of appropriatestrength as to yield a mixture containing about 7 percent. of themodified hydroxy-ethyi cellulose and 7 to per cent of caustic soda.

The washed and pressed reaction mass may also, optionally after havingbeen dehydrated with alcohol and, if desired, exhausted with ether, bedried and thereafter dissolved as described above.

A solution containing 7 per cent. of the modified hydroxy-ethylcellulose and 9 per cent. of NaOH has a viscosity of 6.5 to 7 ascompared with glycerine of 1.26 specific gravity. It filters well at apressure of 4 to 2 atmospheres without change or with a very few changesof the filtering material (cotton). It is possible to obtain from thesolution films which have a dry tenacity of 13700 grammes (13.7kilogrammes) per square millimetre, a wet tenacity of 3550 grammes (3.55kilogram-mes) per square millimetre, a dry extensibility of 24 and a wetextensibility of 115 to 120 per cent.

E. Mode of procedure as in D, but with the variation that, instead ofthe hydrochloric acid of 0.5 per cent. strength, hydrochloric acid of 1to 5 per cent. strength is used;-

Ezample I] The process is carried out as in Example I A or B or C or Dor E, but with the difference that,'instead of at 100 C., the heating isconducted at 105C.

In each of the five cases the product is readily soluble in caustic sodasolution at room temperature, the viscosity'of a solution containing 7per cent. of the modified hydroxy-ethyl cellulose and 9 per cent. ofcaustic soda being, when onset the working formulae of Example I A or Bor C is followed, about 6 and, when Example I D or E is followed, 5 to5.5 ascompared with glycerine of 1.26 specific gravity. From thesolutions which are easily filterable at a pressure of 4 to 2atmospheres shaped structures can be produced which havehighlysatisfactory dynamometric properties.

Example Ill The process is conducted as in Example I A or ing operationis 110 C.

The properties of the final product and of the shaped structuresprepared therefrom are similar to the properties of the product ofExample 11 and of the shaped structures made therefrom.

ares-{e10 Example I? strength, at room temperature (15 to 16 C.)

A solution containing 7 per cent. of the modified hydroxy-ethylcellulose and 9 per cent. of NaOH filters very well at a pressure of 4to 2 atmospheres and has a viscosity of 2.8 ascompared with glycerine of1.26 specific gravity, the viscosity of a solution (made up in the sameproportions) from the parent lwdrorw-ethyl cellulose prepared byfreezing and thawing being 25 to 28 and its filtering capacityconsiderably inferior (10 to 8 atmospheres). Notwithstanding the lowerviscosity, the solution gives shaped structures having very gooddynamometric properties. Thus, for instance films can be obtained thathave a dry tenacity of 13,600 grammes per square millimetre, a wettenacity of 2350 grammes per square millimetre and an extensibility of16 to 20 per cent.

Example V The process is conducted as in Example IV, but with theexception that the duration of the heating is 3 hours 30 minutes insteadof 12 hours.

Example VI The process is conducted as in any one of the precedingexamples, but with the difference that, after the three hours shreddingtaking place in Example I A after the addition of the ethylenechlorohydrin or ethylene oxide, before being washed, the reaction massis allowed to remain at 10 C. for 21 hours.

When this example leans on either of the working formulae given in theExample I A or. B, the resultant product is readfly soluble in causticsoda solution of, say, 8 to 9 per cent. strength at 15 C., givingthereby an easily filterable solution (4 to 2 atmospheres) from whichshaped structures having excellent dynamometric properties can beobtained (e. g. films having a dryv tenacity of about 11,400 and a wettenacity of 2700 grammes per square millimetre and an extensibility of24 to 26 per cent), whereas the parent hydroxy-ethyl cellulose isinsoluble at 15 C. and can be brought into solution only according tothe process-described in my British Patent No. 212,864, for example bycooling its incomplete solution to 0" C. or minus 4 C. or lower.

And, when the working formula given in Example I D is adopted for thisexample, products having the same solubility and filterability result,from which it is possible to obtain shaped structures excelling by stillbetter dynamometric properties (e. g. films having a dry tenacity of12,000 grammes, a wet tenacity of 3000 grammes per square millimetre andan extensibility of 20 to 27 per cent.

In contradistinction to the products of this example, the parenthydroxy-ethyl cellulose is insoluble at 15 C. and can be brought intosolution only according to the process described in my British PatentNo. 212,864,.for example by cooling its incomplete solution to 0 C. orminus 4 C. or lower.

Example VI! The process is conducted as in any one of the Example VIIIThe process is carried out as in any one of the Examples I to V, butwith the difierence that the 3 hours shredding taking place in Example IA after the addition of the ethylene chlorohydrin or ethylene oxide isconducted at 21 C.

instead'of at C.

Example IX The process is conducted as in any one of the Examples I toV, but with the difference that the l to 3 hours shredding occurring inExample I A before, and the 3 hours shredding occurring in Example I Aafter the addition of the ethylene chlorohydrin or ethylene oxide isperformed at 21 C. instead of at 10 C.

Regardless of whether this example leans on anyone of the workingformulae of the Examples I A to C, or on the working formula of ExampleI D, the filterability of the solution is perfectly satisfactory and thedynamometric properties of the shaped structures made from the finalproducts are very good.

Example X The process is conducted as in any one of the Examples I to V,but with the exception that the 1 to 3 hours shredding before, and the 3hours shredding in Example I A after the addition of the ethylenechlorohydrin or ethylene oxide is performed at 21 C. instead of at 10C., and that after the 3 hours shredding which in Example I A occursafter the addition of the ethylene chlorohydrin or ethylene oxide,before being washed, the reaction mixture is allowed to stand at 21 C.for 21 hours.

When in this example either of the working formulae given in the ExampleI A or B is followed, a product is obtained which is readilysoluble incaustic soda solution of, say, 8 to 9 per cent. strength at C. Thesolutions thus obtained (for example a solution containing 7 per cent.of the modified hydroxy-ethyl cellulose and 9 per cent. of NaOH) filtereasily at a pressure of 3 to 2 atmospheres. Still better filterablesolutions can be obtained when the product is after-treated according toExample I D. For, a solution of such after-treated, modifiedhydroxy-ethyl cellulose filters easily at a pressure of ,2 atmospheres,and the shaped structures which can be prepared therefrom have very gooddynamometric properties. Thus, for example, films produced therefromreach a dry tenacity of 11,000 grammes and a wet tenacity of 2500grammes per square millimetre, a dry extensibility of about 30 to 34 anda wet extensibility of about 110 per cent.

In contrast with the products of this example, the parent hydroxy-ethylcelluloseused therein is insoluble in caustic soda solution at 15 C. and

can be made soluble therein only by cooling its of this example preparedin accordance with Example I A or B is about 7 and the viscosity of anequally composed solution of the product of this example madeaccordingfto Example I D is about 4 to 5 as compared with glycerine of1.26 specific gravity.

Example XI Mode of procedure as in Example X, but with the variationthat the duration of the heating of the dried hydroxy-ethyl cellulose at100 C, is one hour instead of twelve hours.

The properties of the products thus obtained are similar to. theproperties of the products of Example X, the only difference being thatthe former are difiicultly soluble in caustic soda solution at 15 C.,but readily soluble therein at 10 C., the filterability of the solutionsand the dynamometric properties of shaped structures made therefromleaving nothing to be desired. 1

Example XII The process is carried out as in any one of Y the Examples Ito Y, but with the difference that, instead of at 10 0., the shreddingof the alkali cellulose, the maturing of the alkali cellulose and theshredding after the addition of the ethylene el5iloohydrin or ethyleneoxide are conducted at Both, the product. of the treatment of thehydroxy-ethyl cellulose thus obtained according to Example I A or B andthe product of the after-treatment of the so modified hydroxy-ethylcellulose according to Example I D, are readily soluble in caustic,sodasolution at 15 C., the solutions thus produced being easily filterable(the former solution at a pressure of 3 to 4 atmospheres and the latterat a pressure of 3 atmospheres). In centradistinction 'to this, theparent hydroxy-ethyl-cellulose of this example is incompletely solublein caustic alkali solution at 15 C. and can be made soluble therein onlyby refrigeration according to the process described in my British PatentNo. 212,864, the solutions thus obtained being difiicultly filterable(10 to 8 atmospheres) and more viscous than the solutions of thehydroxy-ethyl cellulose modified accordingto the present example.

The dynamometric properties of the shaped structures made from productsof the present example are very satisfactory.

Example XIII The process is carried out as in Example XII,

'but with the difference that the shredding after the addition of theethylene chlorohydrin or ethylene oxide is performed at 21 C. instead ofat lose containing T per cent. of the latter and 9 per cent. of NaOH is10 to 11, whilst the viscosity of an equally composed solution of theproduct The products of the treatment of the hydroxyethyl celluloseaccording to Example I A or B and the product of the after-treatmentwith hydrochloric acid according to Example I D are soluble in causticsoda solution at 15 0., the solution of the soured product being veryeasily. filterable at a pressure of 2 atmospheres. From this solutionshaped structures with very good dynamois incompletely soluble incaustic soda solution at 15 C. and can be completely dissolved thereinonly by the refrigeration process described in my British Patent No.212,864.

Example XIV The process is conducted as in Example XIII, but with thevariation that the duration of the heating operation is only 1 hourinstead of 12 hours.

In contrast with the product the product of this example is notabsolutely completely soluble in causticsoda solution at roomtemperature, but only at about to C. Its solutions however are easilyfilterable and capable of yielding shaped structures having very gooddynamometric properties. 1

Example XV The process is conducted as in Example XIII, but with theexception that the shredding after the addition of the ethylenechlorohydrin or ethylene oxide takes place at 21 C., and that thereafterthe reaction mass .is allowed to stand at 21 C. for 21 hours.

Example XVI The process is conducted as in any one of the Examples I toV, but with the difference that, instead of at C., the shredding of thealkali I cellulose and the maturing of the alkali cellulose are carriedout at 25 C., and that the shredding after the addition of the ethylenechlorohydrin or ethylene oxide is carried out at 21 C.

The products of this example are readily soluble in caustic sodasolution at room temperature, the solutions having low viscosities.Thus, for instance; a solution of the product obtained in accordancewith the working formula of Example I A or B containing '7 per cent. ofthe modified hydroxy-ethyl cellulose and 9 per cent. of NaOH has aviscosity of 1.7 to 2 as compared with glycerine of.1.26 specificgravity and an equally composed solution of the product prepared on thebasis of Example I D a viscosity of 1.3 to 1.75 as compared withglycerine of 1.26 specific gravity. .They filter very easily at apressure of 2 atmospheres.

Nevetheless, it is possible to produce from these solutions shapedstructures having very good dynamometric properties (for example, filmshaving a dry tenacity of 10,600 grammes, a wet tenacity of 2300 grammes,a dry extensibility of about 23 per cent. and a wet extensibility ofabout 105 per cent.)

Example XVII The process is conducted as in Example XVI, but with theexception that, after the shredding following the addition of theethylene chlorohydrin or ethylene oxide, the mass is allowed to remainat 21 C. for 21 hours.

Example XIX The process is conducted as in any one of the Examples X toXVIII, but with the difference that the temperature of the heatingoperation is 50 C. instead of 100 or 105 C. This notwithstanding, theproducts (particularly the products of Example XIJI,

foregoing Examples I to XXIII, but with the aiter-treated'in the senseof Example I D) are. readily soluble in caustic soda solution at 15 C.,

thus givingeasily filterable (about 4to 2 atmospheres) solutions whichare capable of being convertedinto shaped structures having very gooddynamometric properties.

Example XX The process is conducted as in any one of the Examples I toV, but with the difference that the duration of the maturing of thealkali cellulose is 144 hours instead of '72 hours.

Example XXI The process is carried out as in any one of the Examples Ito V, but with the following differences:

(a) The shredding .of the alkali cellulose is performed at 15 C. insteadof at 10 C.

(b) The temperature of the maturing of the' into shaped structureshaving very good dyna- I mometric properties. Also in this case it.canbe observed that the modified hydroxy-ethyl cellulose obtained in thisexample when after-treated with acid according to Example I D givesshaped structures which, with regard to their dynamometric properties,are somewhat superior to the shaped structures prepared from themodified hydroxy-ethyl cellulose which has not been so after-treated.

' Example XXII The process is carried out as in Example IQII, but withthe difference that the shredding after the addition of the ethylenechlorohydrin or ethylene oxide is conducted at 21 C., and thatthereafter the reaction mass is allowed to stand at 18 C. for 21 hours.I

Example XXIII Example XXIV -The process is conducted as in any one ofthe foregoing examples, but with the difference that, instead of the 200parts of ethylene chlorohydrin or parts of ethylene oxide, 275 parts ofglycerine-alpha-monochlorohydrin or 250 parts of propylene chlorohydrinor 145 to parts of propylene oxide or 200 to 300 parts of di-ethylsulphate or 200 to 250 parts of di-methyl sulphate or 230 to 240 partsof monochloroacetlc acid, preferably in the form of a strong solution ofits sodium salt, are used.

Example XXV The process is conducted as in any one of the exceptionthat, insteadofthe 200 parts of ethylene chlorohydrin or 110 parts ofethylene oxide, a mixture of 100 parts of ethylene chlorohydrin or of 55parts of ethylene oxide and 100 to 200- I aaeepre parts of di-methylsulphate or di-ethyl sulphate or a mixture of 50 parts of ethylenechlorohydrin or of 27.5 parts of ethylene oxide and 50 to 200 parts ofdi-methyl sulphate'or di-ethyl sulphateisused. I

Example The process is conducted as in any one of the Examples I toXXIII, but-with the difference that, instead of the'200 parts ofethylene chlorohydrin or 110 parts of ethylene oxide, 100 to 110 partsof ethylene chlorohydrin or 55 to 60 parts of ethylene oxide are used.

tion of the ethylene chlorohydrin or ethylene oxide is carried out at 20C. instead of at 10 C.

(d) After this shredding the reaction mass is allowed tostand at 20 C.for 15 hours and then washed.

The resultant product is as such or after having been treatedwith-hydrochloric acid accord ing to Example I D readily soluble incaustic soda solution at C., giving solutions which are easilyfllterable at a pressure of 3 to 2 atmospheres,

- which solutions are capable of beingworked up The modified hydroxy-ethyl cellulose thus obtained is as such .or after having been treatedwith acid according to Example I D only incompletely soluble in causticsoda solution at room temperature. Nevertheless, the viscosity of itssolutions is much lower than the viscosity of the solutions of theparent hydroxy-ethyl cellulose. For example: A solution containing '1per cent. of the parent hydroxy-ethyl cellulose and 9 per cent. oif NaOHhas a viscosity of 25.9 as compared with glycerine of 1.26 specificgravity,

whereas the viscosity of an equally composed so-.

lution of the non-soured, modified hydroxy-ethyl cellulose preparedaccording to this example is 8.4 and the viscosity of the hydroxy-ethylcellulose modified according to this example and after-treated withhydrochloric acid in the sense of Example I D is 4.7 as compared withglycerine of 1.26 specific gravity.

In addition, the filterability oi the solutions of the products of thepresent example is far bet-- ter than the filterabllity oi thesolutionsof the parent hydroxy-ethyl cellulose, a 7 per cent. solutionof the former filtering easily at 6 to 4 (non-soured product) or at 4 to3 atmospheres (soured product), a 6 per cent. solution of the latterfiltering very slowly and with several changes of the cotton at 10 to 8atmospheres.

The shaped structures. obtainable from the solutions of .thehydroxy-ethyl cellulose modified according to this example, have verygood dynamometric properties.

Example XXVI! The process is carried out asin- Example of the alkalicellulose. the maturing or the alkali the ethylene chlorohydrin orethylene oxide is conducted at 21 C. instead of at 10 C. and thatthereafter the reaction'mass'is allowed to re main at 21 C. !or 21hours.

The modified lmdroxy-ethyl cellulose resulting from this example is assuchand in the soured state (see, for instance, Example I D) readilysoluble in caustic soda solution at 0 C. to 5 C., the thus obtainedsolutions displaying excellent filterability. Shaped structures producedthere-. from have very good dynamometric properties.

Example XXVIII The process is conducted as in any one of the Examples Ito V, but with the following 'difierences:

XXVI, but with the exception that the shredding cellulose and theshredding-alter the addition of into shaped structures having very gooddynamometric properties. When the heating is con- T ducted at 120 C.,the product of this exampleis solublein caustic soda solution atl5 C.

Example XXIX inverse proportion to the time of the after-maturing. Whenthe duration of the after-maturing is 24 hours, the soured product issoluble at 0 C., whereas, when theduration of the aftermaturing is 36 to48 hours, both, 'the soured and unsoured product are soluble at plus 10C.

Example XXX The process is conducted as in Example XXVIII, but with thedifference that, instead of for 15 hours, the reaction massresultantfrom the shredding after the addition of the ethylene chlorohydrin orethylene oxide is allowed to remain at 20 C. for 64 hours. I Thnon-soured and the-soured product of this example are readily soluble incaustic soda solution at 10 C., giving solutions which are very easilyfilterable at a pressure'of 2 atmospheres. It is possible to obtaintherefrom shaped structures having verygood dynamometric properties.

Example XXXI I The process is carried out as in any one of the ExamplesXXVIH to XXX, but with the excep- (a) The temperature of the shreddingpreceding the addition of the ethylene'chlorohydrin or ethylene oxide is20 C. instead of 10 C.

(b) Instead of the 200 parts of ethylene em...

rohydrinor 110 parts of ethylene oxide, 100 to 110 parts of ethylenechlorohydrinor to parts of ethylene oxide, are used.

(c) The 3 hours shredding following the addition that, before beingtreated withthe. ethylene 'chlorohydrin or ethylene oxide, thealkalicellulose is allowed to mature for 64 hours at 21 C. I Thecellulose ethers used as parent materials in the foregoing examples mayin the form of the crude reaction masses (when necessary. with addition.of some concentrated caustic alkali solution or solid caustic alkali inreplacement of, or; in excess to, the caustic alkali used up in thereaction) or in the form of the washed and, optionally dried,reactionproducts be treated in presence of alkali with-50 to 200 partsof ethyl chloride or with '70 to 150 parts of propyl chloride or to600parts of benzylchloride at 50 to C. and used as starting materlals'inthe" present invention, for example as described in any one of theExamples I to XXXI. I

Example xxxu The process is conducted as many one ofthe Examples I to V,but'with the difference that, instead of the hydroxy-ethyl celluloseused tliere.-- in as parent material, an ethyl cellulose is used which,for example, may be prepared as follows:

A quantity of any one of the alkali celluloses used for theetheriflcation in any one of the preceding examples, corresponding to1000 partsof air-dry parent cellulose is placed in a rotating autoclaveor an autoclave provided with a stirring device, 200 to 500 parts ofpre-cooled ethyl chloride are added, and the material is heated to 60 to80 C. and kept at this temperature for 12 hours.

The product of the reaction is washed, and thereafter dried and treatedas described in any one of the Examples I to V.

7 Any one of the ethyl celluloses obtained in Ex ample XXXII may behydroxy-alkylated in the following manner:

tions Ser. Nos. 71,250, 71,251, 71,252 and 71,253, and to the ninemethods given in myU. S. application Ser. No. 71,263 and to the examplescontained in these specifications. I

The cellulose ethers prepared according to the present invention areparticularly suitable parent materials for the preparation of celluloseether xanthates by means of small proportions of carable properties.

The NaOH content of the crude reaction mix- I ture resulting from theetbylatlng operation is determined by analysis, whereupon, optionallyafter compensating the amount of NaOH used up in the alkylating reactionby supplying to the reaction mixture the equivalent or a larger quantityof NaOH in the form of .powder or of a strong solution, for instance ofto 50 per cent. strength. the reaction mixture is treated with 50 I to150 parts oi'ethylene'chlorohydrin or 70 to 210 parts of glycerolalpha-monochlorohydrin or with 25 to .75 parts of ethylene oxide or with32 to 100 parts of propylene oxideas described in any one of thepreceding relative examples for alkali cellulose. 1

The thus obtained ethyl-hydroxy-ethyl cellulose or ethyl-lz2-dil'lydroxy-propyl cellulose or ethyl-hydroxy-prop'yl cellulose iswashed and thereafter dried and treated as described in any one of theExamples I to V.

Example XXXIII Example XXXIV The process is conducted as in any one ofthe preceding examples,. but with the difference that the'dry celluloseether is heated for 3 hours at 150 C. instead of for 12 to 24 hours at100 or 105 or 110 or 120 C.

Example XXXV The process is conducted asv in Example mrvr, but with thedifference that the dry hydroxyethyl cellulose is heated for 1 to 2hours at 180 C.

instead of for 8 hours at 150 C.

bon bisulphide according to the process described in my co-pendingapplication Ser. No. 71,263.

The xanthates of the cellulose ethers prepared according to the presentprocess can be worked up into shaped structures excelling by very valu-Since the practice of the processof making 'xanthates of celluloseethers and of working them up into shaped structures is exactly as setforth in the specifications set out in the-foregoing paragraphs andexplained therein by aid of numerous examples, it appears superfluous torepeat here all particulars relating'to the conversion of the celluloseethers prepared according to the invention into their xanthates and tothe working up of .these xanthates into shaped structures and otheruseful articles under various working conditions. V

I therefore limit myself to the following examples:

Example XXXVI An alkali-soluble, water-insoluble cellulose etherprepared according to any one ofthe foregoing examples is converted intoits alkali compound either by alkalizing it with an excess of causticsoda solution of 1a to 20- per cent. strength and removing the excess ofthe caustic soda solution by pressing and thereafter shredding thesodium cellulose ether thus obtained or by mixing in a shredder 1 partof the dry cellulose ether with 2 to 2.5 parts by weight of caustic sodasolution of 18 to 20 per cent. strength.

The sodium cellulose ether obtained according,

to either of the aforementioned two methods is,

option ally after having been matured for 12 to As stated above, thecellulose ethers prepared according to the present invention can beconverted into technically valuable xanthates.

These "xanthatescan be'produced for example according to any one of theprocesses described in my U. 8. Patents Nos. 2,021,861, 1,858,097 and1,910,440 and in my U. B. applications'Ser. Nos.

71,254, 71,255, 71,260, 71,261, 71,262, 71,263 and 71,264.

. In this respect special attention is called by way of example to theseven methods described in my U. 8.- Patent No. 1,858,097, to the ninemethods described in each of-my U. S. applica- 48 hours or longer,treated with 30 to 60 per cent. of carbon bisulphide (based on theweight of the cellulose ether) according to the process described inmy-U. S. Patent No. 1,858,097 or in my U; S. application Ser. No.521,023 or with'8 to 12 per cent. of carbon bisulphide according to theprocess described in my U. S. application Ser. No. 71,263, whereupon thethus obtained cellulose-ether xanthate is dissolved in so much causticsoda solution of appropriate strength as to,

yield a solution containing 7 to 10 per cent. of the cellulose ether(calculated as dry substance) in a caustic soda solution of 6 to 9 percent. strength.

'The thus obtained solution can be worked up into shaped structuresaccording to any method described in my U. 8. applications Ser. Nos.71,250, 71,251, 71,252, 71,258, 71,263 or 521,017 or in my U. 8. PatentNo. 2,021,861.

Example XXXVII 1000 parts of air-dry wood-pulp of a quality andviscosity customary in the viscose art or cotton linters of similarquality are steeped in 10,000 to 20,000'parts of caustic soda solutionof 5 per cent. strength at 15 C. and the mixture allowed to stand at 15C. for 3 to 24 hours. The

resulting mass is then pressed to 1340 parts and comminuted at 15 C. for3 hours in a..Werner- Pfleiderer shredder. Thereupon the alkalicellulose thus obtained is dried under reduced atmospheric pressure at60 C. to constant weight and r for 12 hours.

After that time, the modified ethyl cellulose thus obtained is alkalizedand xanthated as described in the foregoing example.

Example XXXVIII The process is conducted as in Example but with thedifference that the steeping caustic soda solution is a caustic sodasolutionof 2 per cent. strength and that the alkali cellulose is pressedto 2000 parts instead of to 1340 parts.

Instead of being prepared by steeping the cellulose in an excess ofcaustic alkali solution and removing the excess by pressing, in any oneof the preceding examples, the alkali cellulose may be prepared bymixing the cellulose in a suitable mixing apparatus, for example ashredder or a kneading machine or a mill or a disintegrator or an edgerunner or the like with the amount of caustic soda solutioncorresponding with the quantity remaining in the alkali cellulose usedin the relative examples after pressing (for example with 2000 to 2500parts of caustic soda solution of 18 per cent. strength). The mixing ofthe cellulose with the caustic alkali solution may be conducted at roomtemperature or at a temperature above room temperature, for example at24. to C., or with cooling, for example to 15 or 10 C. or lower. Thetime of mixing may be varied within wide limits, for example from 1 hourto 24 hours or longer.

As a guiding line with regard to the question whether or not the alkalicellulose should be allowed to mature before being brought together withthe etherifying agent or agents, may, among others, serve the desiredviscosity of the final solution of the products of the invention in theproduction of which alkalicellulose is used, i. e. of the solution ofthe modified cellulose ether which is to be worked up into shapedstructures, and in connection therewith th viscosity of the kind ofcellulose used as starting material for making the cellulose ether. Ifit' is desired to give the solution a definite viscosity, then thealkali cellulose produced from the kind of cellulose contemplated issubjected to a maturing process, if without maturing this kind ofcellulose yields a higher viscosity. If, however (in a preliminaryexperiment), the solution exhibits from the firstthe desired grade ofviscosity, that is without maturing, the maturing is superfluous. Now,as the viscosities of the difierent kinds of cellulose on the market(linters and wood-pulp) difier very much from one another, the questionof maturing depends in most cases on the one hand on the viscositydesired of the solution intended for the manufacture of shapedstructures, and on the other hand on the viscosity of the kind ofcellulose used as starting material.

drying; or by treating with a strong inorganic or organic acid or amixture of both; or by treating with a dilute solution of a mineralacid; or by treatment with a zinc halide; or by .a mechanical process,such as grinding in presence of water or the like; or an oxycelluloseinshort any body of the cellulose group which has been proposed for themanui'acture oi viscose or of any other cellulose derivatives orcompounds or of 'ammoniacal-copper-oxlde cellulose can be used asstarting material for the production of the cellulose ether.

If feasible or expedient, in the foregoing examples, instead of thechlorinated etneriiying agents used therein, equivalent quantities orthe corresponding brominated or iodinated reagents (for example alkylbromides or alkyl iodides or monobromohydrin or monoiodohydi'ln orethylene bromohydrin or ethylene iodoriydrin or bromo-acetic acid oriodo-acetic acid etc.) may be used.

If feasible or expedient, in the foregoing examples, instead DI thealkylatlng or hydi'oxyal'kylatlng agents usedtherein, equivalentquantities of alkylating or hydroxy-alkylating agents contalning otheralkyl or hydi'oxy-alkyi groups can be used, for instance methyl chlorideor propyl chloride or an amyl chloride or a butyl chloride or butylenechloronydrm.

Ii feasible or expedient, instead of ethylene oxide or propylene. oxide,other alkylene oxides, such as butylene oxide or glycide, in short allsuitable compounds which contain an ethylene oxide ring can be used inthe ioregoing examples.

In the foregoing examples, any excess of the volatile (if any)etherifying agents which has notbeen used up in the etherifying reactionmay be recovered by condensation or distillation.

In the foregoing examples, instead of cellulose,

It feasible or expedient, instead 01 alkyl halides or di-alkylsulphates, equimolecular amounts of their substitution or additionderivatives, ior example halogen alkyl. amines, such as halogenalkyl-clialkyl amines or their hydrochlorldes can be employed in theforegoing examples.

If feasible or expedient, in the foregoing relative examples, instead ofthe chloroacetic acid, the equimole'cular quantity oian ester ofchloroacetic acid, for example methylor ethyl-chloroacetate or a halogenderivative of a homologue of acetic acid, for instancealpha-chloropropionic acid or alpha-isobutyric acid oralpha-bromopropionic acid or alpha-bromo-isobutyric acid or the like oran alkali salt or an ester thereof may be employed.

As stated above, the solutions of the cellulose ethers preparedaccording to the invention may be worked up into shaped structures orother useful articles by any process whatever known or proposed for themanufacture of shaped structures or other useful articles fromalkali-soluble cellulose derivatives, viscose included, for instance bythe process described in my U. S. Patent No. 1,722,928 or by any one ofthe processes described in my U. S. applications Ser. Nos. 521,- 022,71,250, 71,251, 71,252, 71,253, 71,254, 71,255, 71,260, 1,261, 71,262and 91,790, or by the processes described in my U. S. applications Ser.Nos. 63,280 and 79,199.

The directions given in those specifications for the production ofshaped structures from alkalisoluble cellulose ethers in general andfrom alkali-soluble hydroxy-alkyl ethers of cellulose in particular areso thorough and detailed and, in addition, illustrated by so manyexamplesthat, instead of repeating the descriptions and statements inquestion, I prefer to confine myself to a reference to the saidspecifications.

With regard to the processes. or methods for the conversion into shapedstructures of the xanthates of the cellulose ethers prepared accordingto the invention, special attention. is. called by way of example to theprocesses of my U. S. applications Ser. Nos. 90,819 and 90,820 which,when applied to the xanthates of the present cellulose ethers, yieldexcellent shaped structures, at the same time economizing theirproduction.

If desired, the extensibility of the shaped structures, such as threadsor film or coatings or the like produced according to the presentinvention from the straight cellulose ethers or from their xanthates maybe increased by treat-' ing them either in the course of theirmanufacture, for example after coagulation and washing or in thefinished wet or dry state with suitable shrinking agents, for example,with some of the shrinking agents mentioned in my U. 8. Patents Nos.1,989,098, 1,989,100, 1,989,101, 2,001,621, 2,004,875 and 2,004,876.

In the specification and claims, wherever the context permits, theexpressions "alkali-soluble cellulose ether, cellulose ether which issoluble or at least partially soluble in caustic alkali solution" andcellulose ether which is at least partially soluble in caustic alkalisolution" are intended to include such simple and mixed cellulose ethersand such cellulose ether-esters as are completely or almostcompletelysoluble in caustic alkali solution at room temperature and ata I lower temperature, for example at a temperature between roomtemperature and C. or lower and such simple and mixed cellulose ethersand such cellulose ether-esters as are insoluble or incompletely solublein caustic alkali solution at room temperature, but as can be madesoluble or completely soluble therein at room temperature by coolingtheir suspensions or incomplete solutions in caustic alkali solution toa temperature between room temperature and 0 C. or to 0 C. or to atemperature below 0 C., for example to minus C. or to minus C. or lowerand then allowing the temperature to rise to 0 C. or above 0 C., forexample to a temperature between C. and 20 C., and such simple or mixedcellulose ethers and such cellulose ether-esters as are insoluble orincompletely soluble in caustic alkali solution at room temperature orat a temperature between room temperature and 0 C. or even at 0 C., butas can be made partially or completely soluble therein at roomtemperature and/or at a temperature between room temperature and 0 C. orat 0 C. by cooling their suspensions or incomplete solutions to atemperature below 0 C., for example to minus 5 C. or minus 10 C. orlower and then allowing the temperature to rise to 0 C. or above 0 C.,for-example to room temperature.

The term cellulose" used in the description and claims is, wherever thecontext permits, intended to include cellulose, its conversion andoxidation products, such as cellulose hydrate, hydrocellulose,oxycellulose, acidcellulose and the like. in short, any body of thecellulose group which has been proposed as startingmaterial for thepreparation of cellulose derivatives or cellulose compounds of any kind.

Wherever the context permits, the term alkali cellulose" means alkalicellulose prepared in the usual manner, namely bysteeping cellulose incaustic alkali solution and removing the excess of the latter bypressing, or by mixing cellulose with such an amount of caustic alkalisolution as is desired to be present in the final alkali .cellu-' lose.

- The expression etherification used "in the specification and claimscovers alkylation or aralkylation or hydroxy-alkylation or, productionof hydroxy-acid derivatives, ether" covers simple alkyl or aralkyl andhydroxy-alkyl or hydroxy-acid ethers and also mixed ethers, for examplethe mixed ethers hereinbefore named.

The term hydroxy-alkyl" is intended to include the halogenated ornon-halogenated radicals of dior poly-valent alcohols in conjunctionwith one or more oxygens or hydroxyls.

Wherever the context permits, the terms alkyl, alkylate," alkylatingagent, alkylation are intended to include unsubstituted or substituted(for example aralkyl groups) alkyl groups, alkylate with alkylatingagents that contain unsubstituted or substituted (for example aralkylgroups) alkyl groups, alkylating agents that contain unsubstituted orsubstituted (for example aralkyl groups) alkyl groups, alkylation with9.1- kylating agents that contain unsubstituted or substituted (forexample aralkyl groups) alkyl groups.

The term hydroxy-alkylating agents is intended to include halogenderivatives of di or polyhydric alcohols, particularly halohydrlns, suchas monohalohydrins and alkylene oxides.

In the specification and claims the expression halogen fatty acid ormonohalogen fatty acid includes, wherever the context permits, monochlor-, monobromand mono-iodo-fatty acids themselves, their derivatives(such as esters) and their salts, as well as substances and mixtures ofsubstances which yield monohalogen fatty acids or their derivatives.

The expression "shaped structures used in the specification and claimsis intended to include: Artificial threads, particularly artificial silkand staple fibre, artificial hair, artificial straw, film of every kind,bands and plates of every kind, plastic masses of anydescription;adhesives and cements, finishes, coatings and layers of every kind,particularly such as are applicable in finishing, filling and dressingof textile fabrics, sizing of yarn, thickening agents or fixing agentsfor pigments in textile printing and the like; paper-like surfacing,paper-sizing; in the manufacture of artificial leather or of book clothor of tracing cloth or of transparent paper or of transparent cloth andthe like.

The term artificial threads denotes artificial threads and spun goods orall kinds, for instance artificial silk, artificial cotton, artificialwool, artificial hair and artificial straw of any kind.

The term hydroxy acid residue" used in the appended claims is intendedto cover that part of a hydroxy acid after the removal of the hydrogenatom of the hydroxyl group, thus HO-CHz-COOH is hydroxyacetic acid andO--CH2COOH is the hydroxyacetic acid residue.

What I claim is:

1. The process which comprises heating, at a temperature between 40 C.and about 250 C. for a period ranging from 12 to 24 hours at the lowertemperature limit to about 5 minutes at the higher temperature limit, aneutralized, washed and dried cellulose ether obtained by reactingalkali cellulose with an etherifying agent in the proportion of 1 mol.of etherifying agent to 2 to 8 C6H10Q5 units, and which cellulose ethercan be dissolved in dilute caustic alkali solution only at substantiallybelow 0 C., said heating being conducted entirely in an inertenvironment free from acids stronger than carbonic acid, and

free from the anhydrides of acids stronger than carbonic acid, wherebyalkali solubility, viscosity characteristics and dynamometric propertiesof said ether are improved.

2. The process which comprises heating, for

about 12 to 24 hours at a temperature of about 100 C. a neutralized,washed and dried cellulose ether obtained by reacting alkali cellulosewith an etherifying agent in the proportion of 1 mol.

of etherifying agent to from 2 to 8 CeHmOs units, 0

l and which cellulose ether can be dissolved in dimometric properties ofsaid ether are improved.

LEON LILIENFELD.

